1. Field of the Invention
This invention relates, generally, to methods for sealing biopsy tracts. More particularly, it relates to apparatus and methods that enable precise positioning of a bioabsorbable sealant plug in a predetermined optimal location.
2. Description of the Prior Art
Air leaks commonly occur at pulmonary tissue sites that have been dissected during surgical resection and manipulation or surgical resection or manipulation. Air leaks also occur after fine needle aspiration biopsy of the lung. Pneumothorax (air leakage) occurs in about thirty per cent (30%) of lung biopsies. An opening in a lung is undesirable because air leaks therefrom and causes the lung to collapse. Openings in other organs, such as the heart, liver, kidney and the lime are also undesirable due to excess bleeding and other related problems.
Pending patent application Ser. No. 10/063,620, filed May 6, 2002 by the present inventors discloses a novel hydrogel polymeric base material formed into the shape of a plug to seal a biopsy tract to prevent pneumothorax in the lungs and bleeding in other internal organs. That pending patent application is incorporated by reference into this disclosure.
There remains a need, however, for apparatus and methods for accurately delivering the sealant plug under CT imaging and other imaging modalities and deploying it with a high degree of precision to achieve optimal efficacy.
The sealant plug must be placed beyond the pleura of the lung to prevent pneumothorax. Accurate placement is required for any depth and position of the biopsy or tissue tract. Such accurate placement must also be made for other internal organs such as the liver, kidney, the heart, i.e., the sealant plug must be positioned at or beyond the surface of such organs to prevent or eliminate bleeding.
There is also a need for a sealant plug having a faster rate of hydration than the plugs heretofore known. One of the most important parameters of a sealant plug is the expansion rate and its ability to seal a tract in a short period of time.
A sealant plug is needed that provides a faster expansion rate than the sealant plugs heretofore known so that it will seal a tract faster, thereby reducing pneumothorax in a lung and bleeding in other internal organs.
However, in view of the prior art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how such apparatus and methods and improved sealant plugs could be provided.
The long-standing but heretofore unfulfilled need for a delivery system for accurately placing a bioabsorbable sealant plug in an optimal location in a biopsy tract is now met by a new, useful, and nonobvious invention. The novel method includes the steps of performing a biopsy procedure with a biopsy needle and a coaxial needle having a movably mounted marker thereon. When the biopsy procedure is finished, the biopsy needle is removed from a biopsy tract formed by the procedure. The coaxial needle is left in the biopsy tract in the same position it was in during the biopsy procedure.
A distance xe2x80x9caxe2x80x9d is measured by an imaging means from a point of entry by the biopsy needle at a skin surface to the surface of the internal organ upon which the biopsy procedure was performed.
A distance xe2x80x9cbxe2x80x9d is measured by the imaging means from the surface of the internal organ at the point of entry to a lesion within the internal organ.
Where a sealant plug of cylindrical configuration having a preferred length of about two and one-half centimeters (2.5 cm) is used, a distance xe2x80x9cdxe2x80x9d is calculated by adding two centimeters (2.0 cm) to distance xe2x80x9ca.xe2x80x9d If a plug having a length of 1.5 cm is used, distance xe2x80x9cdxe2x80x9d is calculated by adding 1.0 cm to distance xe2x80x9ca.xe2x80x9d If a plug having a length of 3.0 cm is used, distance xe2x80x9cdxe2x80x9d is calculated by adding 2.5 cm to distance xe2x80x9ca.xe2x80x9d The distance added to distance xe2x80x9caxe2x80x9d must position the leading end of the plug at a depth in the biopsy tract such that about one-half centimeter (0.5 cm) of the trailing end of the plug protrudes out of the biopsy tract, beyond the surface of the lung or other internal organ, for a plug of any length. Thus, half a centimeter is subtracted from the length of the sealant plug, and that length is added to distance xe2x80x9caxe2x80x9d to arrive at distance xe2x80x9cd.xe2x80x9d After the biopsy procedure has been completed and the biopsy needle has been removed from the lumen of the coaxial needle and distance xe2x80x9cdxe2x80x9d has been calculated, the coaxial needle is advanced or retracted as needed so that its distal end is distance xe2x80x9cdxe2x80x9d from the surface of the patient""s skin. Centimeter markings or graduations are imprinted, notched, or otherwise marked on the coaxial needle, beginning from its distal end.
More particularly, suppose a plug of length 2.0 cm is used and distance xe2x80x9cdxe2x80x9d is therefore calculated by adding 1.5 cm to distance xe2x80x9caxe2x80x9d so that the trailing end of the plug will protrude from the biopsy tract by 0.5 cm when the plug is properly positioned. If distance xe2x80x9caxe2x80x9d is 3.0 cm, then distance xe2x80x9cdxe2x80x9d is equal to 4.5 cm. If the distal end of the coaxial needle is less than 4.5 cm from the surface of the patient""s skin at the conclusion of the biopsy procedure, the marker on the coaxial needle is moved to the 4.5 cm position and the coaxial needle is advanced until the marker abuts the patient""s skin. If the coaxial needle is more than 4.5 cm beneath the patient""s skin at the conclusion of the biopsy procedure, the marker is moved back if needed and the coaxial needle is withdrawn until the 4.5 cm marker thereon is flush with the patient""s skin and the movable marker is then brought into contact with the patient""s skin.
A supporting leg and a plunger are then connected to one another and their respective positions relative to one another are adjusted in accordance with a chart containing predetermined settings including a plunger-to-supporting leg ratio with respect to measurement of said distance xe2x80x9ca.xe2x80x9d Graduation markers on the plunger are provided to facilitate the interconnection. The plunger is then locked into position relative to the supporting leg, thereby forming a plunger/supporting leg assembly.
The sealant plug is then introduced into the coaxial needle at the trailing end thereof. The assembly is then brought into ensleeving relation with the coaxial needle. Specifically, the leading end of the supporting leg is positioned in abutting relation to the patient""s skin. The leading end of the plunger enters into the trailing end of the lumen of the coaxial needle, pushing the sealant plug ahead of it in a trailing-to-leading direction. When the leading end of the supporting leg abuts the patient""s skin, the sealant plug is still housed within the lumen of the coaxial needle, but it is positioned at the desired position. Specifically, the leading end of the sealant plug is flush with the leading end of the coaxial needle.
The coaxial needle is then removed from the biopsy tract while maintaining the supporting leg and the plunger in their respective positions, thereby deploying the sealant plug into the biopsy tract. The trailing 0.5 cm of the sealant plug protrudes from the biopsy tract, above the surface of the internal organ having the lesion that was the subject of the biopsy. The supporting leg and the plunger are then withdrawn, leaving the sealant plug in said internal organ at said preselected optimal position.
In a second embodiment, the method for delivering a sealant plug to an optimal position within an internal organ with a high degree of accuracy includes the steps of providing a supporting leg in the form of a pistol grip body that includes a pivotally-mounted trigger. A plunger is mounted to the supporting leg such that the plunger may be advanced or withdrawn when the trigger is pulled. A marker is slideably mounted on the plunger and graduation marks are provided along the extent of said plunger. Graduation marks are also are imprinted or otherwise provided along the extent of the supporting leg.
As in the first embodiment, distance xe2x80x9caxe2x80x9d is determined and a distance xe2x80x9cdxe2x80x9d is calculated by adding to distance xe2x80x9caxe2x80x9d a distance, in centimeters, that is 0.5 cm less than the length of the sealant plug in centimeters. A marker is used as in the first embodiment to denote the desired depth and the distal end of the coaxial needle is positioned at said depth.
With the trigger pulled to allow movement of the plunger, the plunger and the supporting leg are positioned relative to one another as determined by a setting provided by a chart as in the first embodiment, and locked together to form an assembly by releasing the trigger. The positioning is performed by aligning a graduation mark on the plunger with a graduation mark on the supporting leg in accordance with said chart.
A sealant plug is then introduced, using a suitable holding tool, into the lumen of the coaxial needle at the trailing end thereof and the plug is pushed in a trailing-to-leading direction with a leading end of the plunger until the leading end of the supporting leg abuts the patient""s skin as in the first embodiment. The sealant plug is then positioned within the coaxial needle such that the leading end of the sealant plug is flush with the leading end of the coaxial needle. The coaxial needle is then withdrawn from the internal organ and from the patient""s body while maintaining the position of the plunger. The plunger/supporting leg assembly is then removed and optimal positioning of the sealant plug is thereby obtained.
A third method for delivering a sealant plug to an optimal position within an internal organ with a high degree of accuracy includes the steps of providing a plunger in the form of a tube having a slot formed in its distal end so that the distal end is bifurcated into two arm members. An inside diameter of the tube is configured so that the inside diameter is smaller than an outside diameter of the sealant plug. The plunger is formed of a flexible and resilient material with memory so that the arms may be spread apart from one another. The arms are spread apart from one another and a trailing end of the sealant plug is positioned between the open arms. The tube is ensleeved in a sleeve member and the sleeve member is advanced in a trailing-to-leading direction, thereby causing the arms to close with respect to one another. Thus, the arms clamp down on the sealant plug. The sealant plug is positioned at a predetermined optimal position by following the steps of the first two embodiments and the sleeve member is retracted so that the arms spread apart from one another under their inherent bias, thereby releasing the sealant plug at the optimal position. The plunger and sleeve member are then withdrawn, leaving the sealant plug in the optimal position.
A fourth method for delivering a sealant plug to an optimal position within an internal organ with a high degree of accuracy includes the step of providing a cylindrical housing having screw threads formed on an external surface thereof and having a longitudinally-extending throughbore formed therein. A screw-threaded turning nut screw-threadedly engages the screw threads formed in the external surface of the cylindrical housing. The turning nut has a central hub that includes a leading end that extends into a trailing end of the bore formed in the cylindrical housing. A centrally apertured flat washer is positioned in leading relation to the leading end so that the flat washer is constrained to displace in a trailing-to-leading direction when the turning nut is advanced. A flexible and resilient gasket of frusto-conical configuration and having a central throughbore formed therein is positioned in leading relation to the flat washer so that the flexible and resilient gasket is also constrained to displace in a trailing-to-leading direction when the turning nut is advanced. A diameter-reducing taper is formed in the longitudinally-extending throughbore so that the throughbore has a reduced diameter leading end. The turning nut is advanced so that the leading end thereof bears against the flat washer and the flat washer bears against the trailing end of the flexible and resilient gasket, thereby driving the gasket into the reduced diameter leading end of the throughbore. The diameter-reducing taper serves to gradually compress the flexible and resilient gasket into the reduced diameter leading section as the turning nut is advanced. The trailing end of the sealant plug is positioned within the central aperture of the flat washer and the central throughbore of the flexible and resilient gasket so that the trailing end of the sealant plug is compressed as the flexible and resilient gasket is driven into the reduced diameter bore, thereby locking down on that part of the sealant plug disposed within the flat washer central aperture and central bore of said flexible and resilient gasket.
A fifth method for delivering a sealant plug to an optimal position within an internal organ with a high degree of accuracy includes the step of positioning a coaxial needle at a predetermined depth by employing an imaging means to determine a distance between a patient""s skin surface and the surface of an internal organ just as in the earlier embodiments.
A positioning adaptor is provided and a supporting rod and a coaxial needle are interconnected to one another with the positioning adaptor to guide the supporting rod with respect to the coaxial needle. A supporting adaptor is provided for interconnecting the supporting rod and a plunger to one another. The supporting adapter is locked to the supporting rod. The relative positioning of the supporting rod and the plunger are adjusted based upon a chart as in the earlier embodiments, and the supporting rod and plunger are locked into position. A sealant plug is introduced into the lumen of the coaxial needle, at the trailing end thereof as in the other embodiments, and the plunger is advanced in a trailing-to-leading direction through said lumen, pushing the sealant plug in front of it until the leading end of the supporting rod abuts the patient""s skin, thereby stopping the trailing-to-leading travel of the plunger as in the earlier embodiments. The supporting rod has a flat, atraumatic distal end that rests against the surface of the skin without imparting trauma thereto. As in the earlier embodiments, the leading end of the sealant plug is flush with the leading end of the coaxial needle when the leading end of the supporting rod abuts the patient""s skin. The supporting rod and plunger are held in place while the coaxial needle is withdrawn from the biopsy tract. The plunger/supporting rod assembly is then withdrawn, leaving the sealant plug optimally positioned in the biopsy tract. i.e., with its trailing end protruding from the outer surface of the internal organ by a distance of about 0.5 cm.
Different dehydration techniques and different shapes and sizes have some effect on the expansion rate of a sealant plug. Another method of changing the expansion rate of the materials disclosed in the incorporated patent application is to induce stress in the polymer. A smaller in size stress induced sealant plug could be used in applications where more dwell time is needed during delivery and where a faster expansion rate is required after deployment. Stress may be introduced in three different forms:
1. During the dehydration process;
2. After the dehydration process; and
3. During delivery and deployment of a sealant plug using a unique delivery system.
A method of pre-stressing a dehydrated sealant plug so that it hydrates at a faster rate than a dehydrated sealant plug that has not been pre-stressed includes the steps of grasping a first end of the sealant plug with a first holder, grasping a second end of the sealant plug with a second holder, and separating the holders from one another to apply tension to the sealant plug.
The amount of stress is correlated with the expansion rate of the sealant plug. The stress can be induced gradually by pulling, pushing, compressing, rotating or otherwise momentarily deforming the sealant plug during the dehydration process. This is most efficiently achieved by special fixturing and machinery.
The stress may also be induced by the same techniques after the dehydration process is completed. Stress can be induced from one per cent (1%) to ninety-nine per cent (99%), but the working range is between twenty-five per cent (25%) to seventy-five per cent (75%). One of the methods is to stretch the dehydrated sealant plug by pulling it using special fixtures. Other methods include compression force and torque applied to the sealant plug. Expansion rates of two to five times faster than unstressed sealant plugs may be achieved by this method. Optimum results have been achieved by providing two (2) to three (3) times the expansion rate due to fifty per cent (50%) induced stress.
A delivery system that can stretch a sealant plug before or during delivery may also induce expansion rate-enhancing stress.
An important object of this invention is to provide an apparatus for delivering and deploying a bioabsorbable sealant to a predetermined optimal location in a biopsy tract with a high degree of accuracy.
Another major object is to teach the art an ideal sealant plug deployment.
Another object is to achieve optimal efficacy by providing a sealant plug having a rate of hydration that is faster than the sealant plugs of the prior art while providing a smaller implant.
These and other important objects, advantages, and features of the invention will become clear as this description proceeds.
The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts that will be exemplified in the description set forth hereinafter and the scope of the invention will be indicated in the claims.